(NON-CEPH). Please help me ID this tooth!


TONMO Supporter
Nov 19, 2002
Attached is a picture of a tooth I found in the 100mya clays at Folkestone in Kent (UK). I suspect it might be some form of marine reptile, though I do not think it is conical enough. Another option might be that it is from some form of marine crocodile.

It is beautifully preserved, even down to the enamel and is just over 1.5 inches long. There are no serrated edges to the tooth though it does have two slight ridges extending from the root to the tip.

Any help in identifying this tooth would be appreciated.

Thanks very much, John.

I think you might be right about the crocodilian form. However, It could not be a thecodont because it simply is not old enough; this tooth is early Cretaceous and the thecodonts existed in the Triassic. However, if I remember rightly, the thecodonts were the ancestors of the crocodilians so, as you point out, there should be a similarity.

I'll see if I can find some pictures of crocodile and thecodont teeth to compare.

Actually, maybe I'm a little rusty on the lingo (its been years since my last herp class), but I think "thecodont" also deals with the style of dentition (in this case, crocodilians). I may be wrong. I need to look it up.

You know, I totally forgot about the Thecodonts themselves... Soooo... Yeah, I should look that up.

I still think its reptilian. You said it was about 110 myo? What was the particular strata in which you found the tooth back then?

This is interesting... :biggrin2:
Heya Phil...

Yeah, I looked it up... It seems thecodont dentition is a form of dentition first found in the Thecodonts themselves. Its a type of dentition where the roots of the teeth are in sockets (alveoli) in the jawbone. And yes, that's the type Crocodilians have.

I think you have a Croc tooth, but as to freshie or saltie I have no clue.

Howdo John.

Thanks for the information as ever.

Just looked 'Thecodont' up in the Collins English dictionary. It seems that the word is indeed a noun and an adjective. Here's what it said:


1 (of mammals and certain reptiles) having teeth that grow in sockets
2 of or relating to teeth of this type

3 any extinct reptile of the order Thecodontia, of Triassic times, having teeth set in sockets: they gave rise to the dinosaurs, crocodiles, pterodactyls, and birds
[ETYMOLOGY: 20th Century: New Latin Thecondontia, from Greek theke case + -odont]

Seems you learn something every day!

Thanks again.......

The Thecodont Hunter.

I watched a programme featuring many shots of crocodiles last night on BBC1 (even though it was about the Loch Ness Monster, don't ask). I must admit, I was struck by similarity of crocodile teeth to my fossil, even down to the ridges. I think you are right!

I can only assume it came from a 100 million year old marine crocodile as it was found in a clay deposit containing numerous belemnites, bivalves, ammonites, crinoid stems, etc. None of those are known from freshwater deposits as far as I am aware.

Thanks again!
No problem, Phil... Actually, I was remembering my herpetology classes and my internship in Florida, where the gators are large and in charge. Crocodilians (both freshies and salties) tend to have the same teeth styles. And heck, the thecodont dentition has been aorund long enough right?


Sushi and Sake,

I would say it is Mosasaur, seems to me croc teeth are straighter and more conical. Check the links below and compare some of them to your specimen. The root looks a little different but they have the same recurved shape.

Mosasaur Teeth 1
See the SOLD specimen

Mosasaur Teeth 2
at the bottom of the page

Let me know what you think. Remember, I'm not the Crocodile Hunter.

:ammonite: :nautilus: :ammonite: :nautilus:
Thanks for the link, Kevin.

Hmmm.....................Mosasaur tooth, could be?

Attached is a photo of four Mosasaur teeth from Cretaceous period Morocco to compare placed next to my mystery tooth. These teeth seem to have a much rounder cross section than my tooth and have subtle striations running from the root to the tip, a feature that my tooth does not have. They also seem to be more conical. As you can see from the other (slightly blurry) attached photo, my tooth is very flat in profile.

(Apologies for the lack of scale, I can't seem to locate my tape measure. The mosasaur teeth are about 30mm).

Increasingly confused.......
I had a look at some mosasaur and croc teeth in the museum the other day. Seems that the cretaceous mosasaur they have has teeth that are slightly recurved and almost square, two opposite corners of which are ridges running from the tip to the root (no serrations), but a few towards the back of the jaw were compressed a little, they had very faint striations. All the Croc teeth they have had fairly strong striations running from the tip to the root, some are conical, and some are compressed, some are straight and some are recurved, they are mostly Jurassic fresh water crocs. I didnt see any pliosaur or pleisiosaur teeth to compare. I guess we need a vertebrate expert here on tonmo.

Good Luck. :ammonite:
Thanks for looking for me, Kevin.

I must admit, I am leaning back towards the mosasaur origin myself due to the lack of striations; the tooth really is quite smooth apart from the two slightly raised ridges. I had thought that, just possibly, the tooth had worn smooth due to abrasion as it was found washed out amongst some shingle on the beach surrounded by clay boulders, but I'm sure the tooth would have been polished all over, not just the crown, if this had happened.

I have seen plesiosaur teeth before in the BMNH in London and these appear more conical with clear scriations, like a croc.

Oh maybe I should just give up! Back to day job for me.........

Send it into the Natural History Museum, care of Simone Wells (see below). The museum undertake identifications, for free, as part of their responsibility to the Great British Public. It'll get named down to species if possible. You can mail it, but I'd recommend going in in person (make an appointment though) and that way you won't have the risk of the thing getting lost in the post. The museum has tonnes of Gault Clay fossils, and identifying this beastie should be quite easy.




Simone Wells
Enquiries Officer
Department of Palaeontology
The Natural History Museum
Cromwell Rd
London  SW7 5BD
020 7942 5482
[email protected]

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